[lexer] Re-kajigger the states for numbers

lexer/src/states/number/prefix.rs

@@ -0,0 +1,68 @@
+/* lexer/src/states/number/prefix.rs
+ * Eryn Wells <eryn@erynwells.me>
+ */
+
+use super::{Radix, Exact};
+use states::{State, StateResult};
+use states::number::Builder;
+use token::Token;
+
+#[derive(Debug)] pub struct Prefix(Builder);
+#[derive(Debug)] pub struct Hash(Builder);
+
+impl Prefix {
+    pub fn new(b: Builder) -> Prefix {
+        Prefix(b)
+    }
+
+    pub fn with_char(c: char) -> Option<Prefix> {
+        let mut builder = Builder::new();
+        if let Some(ex) = Exact::from(c) {
+            builder.push_exact(ex);
+        } else if let Some(rx) = Radix::from(c) {
+            builder.push_radix(rx);
+        } else {
+            return None;
+        }
+        Some(Prefix::new(builder))
+    }
+}
+
+impl State for Prefix {
+    fn lex(&mut self, c: char) -> StateResult {
+        match c {
+            '#' => StateResult::advance(Box::new(Hash(self.0))),
+            _ => StateResult::fail(format!("invalid char: {}", c).as_str())
+        }
+    }
+
+    fn none(&mut self) -> Result<Option<Token>, String> {
+        Err("blah".to_string())
+    }
+}
+
+impl State for Hash {
+    fn lex(&mut self, c: char) -> StateResult {
+        if let Some(ex) = Exact::from(c) {
+            if !self.0.seen_exact() {
+                self.0.push_exact(ex);
+                StateResult::advance(Box::new(Prefix::new(self.0)))
+            } else {
+                StateResult::fail(format!("invalid char: {}", c).as_str())
+            }
+        } else if let Some(rx) = Radix::from(c) {
+            if !self.0.seen_radix() {
+                self.0.push_radix(rx);
+                StateResult::advance(Box::new(Prefix::new(self.0)))
+            } else {
+                StateResult::fail(format!("invalid char: {}", c).as_str())
+            }
+        } else {
+            StateResult::fail(format!("invalid char: {}", c).as_str())
+        }
+    }
+
+    fn none(&mut self) -> Result<Option<Token>, String> {
+        Err("blah".to_string())
+    }
+}